FairCom JDBC

Record/Row Locking

<faircom>\drivers\sql.jdbc\tutorials\JDBC_Tutorial3.java

Now we will explore row/record locks using the FairCom DB JDBC Interface.

The functionality for this tutorial focuses on inserting/adding rows/records, then updating a single row/record in the customer master table under locking control. The application will pause after a LOCK is placed on a row/record. Another instance of this application should then be launched, which will block, waiting on the lock held by the first instance. Pressing the <Enter> key will enable the first instance to proceed. This will result in removing the lock thereby allowing the second instance to continue execution. Launching two processes provides a visual demonstration of the effects of locking and a basis for experimentation on your own.

As with all other examples in the c-tree tutorial series, this tutorial simplifies the creation and use of a database into four simple steps: Initialize(), Define(), Manage(), and you’re Done() !

Tutorial #3: Locking

Here we demonstrate the enforcement of data integrity by introducing record/row "locking".

Initialize() - Connects to the FairCom Database Engine.
Define() - Defines and creates a "customer master" (custmast) table/file.
Manage() - Adds a few rows/records, manipulates them, and displays the results.
Done() - Disconnects from FairCom Database Engine.

Note our simple Main() function:

import java.sql.*;

import java.io.*;

public class JDBC_Tutorial3 {

static Connection conn;

static Statement stmt;

// main()

// The main() function implements the concept of "init, define, manage

// and you're done..."

public static void main (String[] args)

throws java.io.IOException

{

Initialize();

Define();

Manage();

Done();

System.out.print("\nPress <ENTER> key to exit . . .");

System.in.read();

System.exit(0);

}

We suggest opening the source code with your own editor.

Continue now to review these four steps.

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